1. Preheat oven to 160 degrees.
2. Beat butter, vanilla, sugar and egg yolks with an electric beater until just combined. Stir in almond meal, flour and baking powder, mix well.
3. Roll tablespoons of mixture into balls; place on ungreased oven trays 5cm apart.
4. Press a hollow into each ball about 1cm deep and 1.5cm wide using the handle of a lightly floured wooden spoon or clean finger.
5. Carefully spoon a little of the jam into the cookies.
10. Bake about 25 minutes. Cool on trays.